Facebook (NASDAQ: FB) could be one of the most undervalued and underappreciated tech stocks around for one simple reason: Its social messaging solutions could have as many as 1.6 billion users.

On September 3, 2015, Mark Zuckerberg and WhatsApp CEO Jan Koum made this simple but revealing post on Facebook: “WhatsApp now has 900 million monthly active users.” That makes Facebook the most popular messaging application in the world, Britain’s Daily Express reported.

It gives Facebook 1.6 billion messaging customers because the second most popular messaging solution in the world is Facebook Messenger, which has around 700 million users, according to The Daily Express. Add 700 million Facebook Messenger users to 900 million WhatsApp users and you get 1.6 billion. That makes the $19 billion that Mark Zuckerberg paid for WhatsApp Inc. last year seem like a bargain.

Facebook now has a potential audience that could be as large as 1.6 billion, which could make it the most valuable advertising and communications platform in the world. The social network might now have an online presence that could be as great, or even greater, than that of Google Inc. (NASDAQ: GOOG) with a similar potential for profit.

Does Facebook Make Money?

Okay, so Facebook can reach a lot of people, but value investors will still ask the most important question of all: Does it actually make money? The answer provided by our friends over at YCharts is yes with a capital Y.

A quick look at Facebook’s financial data shows that, yes, it is making a lot of money, and its revenue is growing.

Some intriguing highlights from Facebook’s second quarter financials include:

A TTM revenue of $14.64 billion on June 30, 2015, a $4.63 billion increase over June 2014 when Facebook reported a TTM revenue of $10.01 billion.

The figures show us that Facebook is a great company that’s swimming in cash, and it is getting better. Mr. Zuckerberg has figured out how to turn social media into a money machine, and he only seems to have scratched the surface of the business.

Jan Koum hard at work at Facebook in a shot snapped by Mark Zuckerberg himself.

Why Facebook Could Be the Next Google

There is a simple reason why Facebook could be the next Google (NASDAQ: GOOGL). It is tapping into one of the same lucrative sources of revenue: advertising. Some data compiled by Statista show how lucrative Facebook advertising really is.

In 2012 Facebook generated $4.28 billion in advertising revenue. Statista estimated that the income stream grew to $6.99 billion in 2013 and $10.93 billion in 2014. Statista predicted that income will grow to $14.27 billion this year and $17.23 billion next year.

The interesting thing here is that Facebook’s revenue figures seem to prove this hypothesis. The YCharts data clearly shows that Facebook’s revenue grew from $10.01 billion in June 2014 to $14.64 billion in June 2015. The revenue growth seems to be verifying Statista’s prediction, which reminds me of Google.

Google reported advertising revenues of $45.085 billion in 2014 that were growing at a rate of 20%. Google also reported advertising revenues of $11.932 billion for the first quarter of 2015 that were growing at a rate of 14% and ad revenues of $12.402 billion that were growing at a rate of 13%.

If you love cash, you have to love advertising and online advertising in particular. It is extremely lucrative and seems to be getting more lucrative all the time.

WhatsApp’s Global Reach

What’s truly exciting here is that WhatsApp could give Facebook an incredible amount of global reach. Take a look at the percentage of mobile phone users that used WhatsApp in various countries around the world, as estimated by Statista:

South Africa, with a population of 52.98 million people and a gross domestic product of $350.6 billion – 78%

Malaysia, with a population of 29.72 million people and a gross domestic product of $313.2 billion – 75%

Argentina, with a population of 41.45 million people and a gross domestic product of $609.9 billion – 74%

Spain, with a population of 46.77 million people and a gross domestic product of $1.393 trillion – 70%

India, with a population of 1.252 billion people and a gross domestic product of $1.877 trillion – 69%

Mexico with a population of 122.3 million people and a gross domestic product of $1.261 trillion – 67%.

Italy, with a population of 59.83 million people and a gross domestic product of $2.149 trillion – 62%

The Netherlands, with a population of 16.8 million and a gross domestic product of $853.5 billion – 61%

Germany, with a population of 80.62 million and a gross domestic product of $3.72 trillion – 57%

Brazil, with a population of 200.4 million and a gross domestic product of $2.246 trillion – 56%

Saudi Arabia, with a population of 28.83 million and a gross domestic product of $747.4 billion – 56%

Indonesia, with a population of 249.9 million and a gross domestic product of $868.3 billion – 52%

Turkey, with a population of 74.93 million and a gross domestic product of $822.1 billion – 49%

As you can see, WhatsApp is popular in some of the world’s most populous nations and some of the most affluent. Facebook is now capable of reaching a vast audience for its advertising, and it is only scratching the surface of monetization.

Facebook Is Only Scratching the Surface of Social Media Monetization

There are plenty of other money making opportunities it has not even started using yet, such as money transfer. App-based social media money transfer is a fast-growing business as demonstrated by the success of PayPal Holdings’ (NASDAQ: PYPL) Venmo solution.

The volume of Venmo payments grew by 50% during the first and second quarters of 2014 and 29% during the third and fourth quarters of 2014, according to Let’s Talk Payments. During the fourth quarter of 2014, Venmo’s payment volume grew to $906 million, according to PayPal’s own statistics.

The volume of mobile payments processed by PayPal grew by 68% in 2014. The total volume of mobile payments processed through PayPal reached $46 billion in 2014 and accounted for 20% of the payment processor’s business. PayPal estimates that one quarter of all the payments it made in 2014 were sent through a mobile device.

Facebook could be sitting on a payment gold mine it could tap by developing its own solution or partnering with PayPal. If it could charge just 1% of those payments, Facebook could have another revenue stream to rival advertising.

Is Retail the Next Frontier of Social Media?

As you can see, the potential market for social media payment solutions is vast, and it is growing. Payments are, of course, only one potential area that Facebook could tap; there is also shopping and even vending machine payment, which is being pioneered by China’s answer to Facebook: WeChat from Tencent Holdings (OTC: TCTZF).

Both WeChat and the South Korea’s highly successful app KakaoTalk are pioneering retail sales through apps, CNET reported. Tencent has partnered with Haier to sell appliances through WeChat, and KakaoTalk lets its users send friends and family “vouchers,” which can be used to make retail purchases.

Facebook could be the technology company with the most growth potential out there. If Jan Koum and Mark Zuckerberg play their cards right, they might be able to create a platform that could be bigger and richer than Google. Those looking for the next Google would be well advised to look into Facebook; it seems underpriced right now.

Disclosure the blogger and author of this piece owns shares of PayPal.